Prepare the balsamic glaze: In a small saucepan, combine balsamic vinegar and honey. Bring to a simmer over medium heat. Cook, stirring occasionally, until the mixture has reduced by about half and coats the back of a spoon, about 5-7 minutes. Remove from heat and whisk in olive oil. Season with salt and pepper. Set aside to cool.

In a large bowl, gently combine the cubed watermelon, crumbled feta cheese, chopped mint, thinly sliced red onion, and diced cucumber.

Drizzle about half of the cooled balsamic glaze over the salad. Toss very gently to combine, being careful not to break up the watermelon too much.

Taste and adjust seasoning if needed. Add more salt and pepper, or a little more glaze, according to your preference.

For best results, let the salad sit for about 5-10 minutes to allow the flavors to meld.

Serve immediately, with any remaining balsamic glaze on the side for drizzling.